Improvement in lamp-chimneys



UNITED STATEs PATENT OEEIoE.

EDWARD w. ELAOKHALL, O TORONTO, ONTARIO, CANADA.

IMPROVEMENT IN LAMP-CHIMNEYS.

Specification forming part of Letters Patent No. 196,328, dated October 23, 1877; application filed June 27, 1877. i

To all whom it may concern:

Be it known that I, EDWARD WAKEFIELD BLAOKHALL, of the city of Toronto, in the county of York and Province of Ontario, Canportions of the glass, a high and even temperature, not susceptible to the sudden variation to which other port-ions of the glass are subject, and thereby forming what may be termed expansion-j oints, whose elasticity relieves any less elastic portion of the glass when subjected to contraction from a blast of cold air.

The said effect is produced by a light metallic wire suspended or otherwise supported within or without the glass to be protected, and shaped so as to follow the contour of the said glass, fitting to, though not necessarily touching,it.

The figure represents my glass-protector suspended within an ordinary lamp-chimney.

It is well known that lamp glasses or chimneys are often broken by a draft of cold air striking a portion of the glass, and causing it to contract suddenly.

My object has been to secure a compensating force for this action, and the instrument herein illustrated produces the desired effect.

A is an ordinary lamp-chimney, and B a wire, of copper or any other suitable material. This wire is bent to follow the contour of the glass A, and is formed with a T-shaped head, which rests upon the top of the glass, as shown, supporting the wire in the desired position. When the lamp is lighted this wire becomes heated to a high temperature, and being contained within the glass is protected from any sudden atmospheric change. The wire being a good radiator, as well as a good conductor, a line of the glass running parallel and corresponding with it is maintained at an equivalent temperature, the radiation from the metal being sufficient to compensate for any sudden atmospheric change which afl'ects other portions of the glass remote from the metal radiator, and therefore the said lines, when the lamp is lighted, are always elastic, and form between the two sections of the glass an expansion-joint, which compensates for any undue or sudden contraction at other parts of the glass.

I do not confine myself to any peculiar shape for the wire radiator, or to the manner illustrated for supporting it on the glass, or for the wire placed within or without the glass; but

What I do claim as my invention is- A wire conductor, B, placed Within or without a lamp glass or chimney, A, for the purpose of retaining heat produced therein, and by radiation affecting a line of the glass running parallel and corresponding with each leg of the said wire, which line is thus maintained at an even temperature, not susceptible to any sudden atmospheric change, and thereby forming between the two sections of the glass A an expansion-joint, which compensates for any undue or sudden contraction at other parts of the said glass.

EWD. 'W. BLAGKHALL.

Witnesses GEO. A. AIRD, W. BLACKHALL. 

